this repeats for most of song (five times?), then there is a shift toriff 2a (x4)riff 2b (x2)riff 2a (x2)riff 1c (x2)riff 1a (x2)...that is for a moment riff 2a is substituted for 1a and likewisewith 2b for 1b.

then the rest is back to normal and finally the little outro is riff 1aagain.